How far is Universal from MK?

[JoyEmBee]

While planning our Disney vacation, my husband's only request was that he'd also like to go to Universal's Islands of Adventure. I Googled it and it's about 16 miles from our resort (Wilderness).

I've read about long waits for transportation when traveling from park to park/resort/DTD/etc. Is this due to shuttle delays or general traffic in the area? If we take a cab to Univeral from the resort, should we expect to run into traffic and plan for an hour of travel? Or would it be a regular 16 mile trip, however long that would take (31 minutes according to Google Map)?

Besides taking a cab, what are the other travel options for getting to Universal? We'll be there in December and are not planning to rent a car.